A QuikSCAT climatology of tropical cyclone size
QuikSCAT data of near-surface wind vectors for the years 1999–2008 are used to create a climatology of tropical cyclone (TC) size, defined as the radius of vanishing winds. The azimuthally-averaged radius of 12 ms−1 [ms superscript -1] wind (r12) [r subscript 12] is calculated for a subset of TCs (...
| Main Authors: | , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Geophysical Union
2011
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| Online Access: | http://hdl.handle.net/1721.1/64407 https://orcid.org/0000-0002-2066-2082 |
| Summary: | QuikSCAT data of near-surface wind vectors for the years 1999–2008 are used to create a climatology of tropical cyclone (TC) size, defined as the radius of vanishing winds. The azimuthally-averaged radius of 12 ms−1 [ms superscript -1] wind (r12) [r subscript 12] is calculated for a subset of TCs (N = 2154) whose centers of circulation were clearly identifiable via subjective analysis of the QuikSCAT-analyzed wind field. The outer radius, r0 [r subscript 0], is determined from r12 [r subscript 12] using an outer wind structure model that assumes no deep convection beyond r12 [r subscript 12]. The global median values of r12 [r subscript 12] and r0 {r subscript 0] are 197 km and 423 km, respectively, with statistically significant variation across ocean basins. The global distribution of r12 [r subscript 12] is found to be approximately log-normal, the distribution of r0 [r subscript 0] is quantitatively much closer to log-normal, and the improvement in fit between r12 [r subscript 12] and r0 [r subscript 0] is attributed to the combined effect of the nature of the model employed and the paired distributions of r12 [r subscript 12] and f. Moreover, the normalization employed by Dean et al. (2009) is found to weaken rather than improve the log-normal fit. Finally, within a given storm, both r12 [r subscript 12] and r0 [r subscript 0]tend to expand very slowly with time early in the storm lifecycle and then becomes quasi-constant, though significant variance exists across storms. |
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